ANTARCTICA: Huge Glaciers, Huge Risk

                                        - By Swati Yadav

 Change in Antarctica is resulting in rising temperatures and increasing snowmelt and ice loss. A summary study in 2018 incorporating calculations and data from many other studies estimated that total ice loss in Antarctica due to climate change was 43 giga tons per year on average during the period from 1992 to 2002 but has accelerated to an average of 220 giga tons per year during the five years from 2012 to 2017. Total mass loss over the period 1992–2018 was likely 2720 giga tons for the grounded part of the Antarctic ice sheet.

 Particularly strong warming has been noted on the Antarctic Peninsula. A study in 2009 noted for the first time that the continent-wide average surface temperature trend of Antarctica was slightly positive from 1957 to 2006. Over the second half of the 20th century, the Antarctic Peninsula was the fastest-warming place on Earth, closely followed by West Antarctica, but these trends weakened in the early 21st-century. Conversely, the South Pole in East Antarctica barely warmed last century, but in the last three decades the temperature increase there has been more than three times greater than the global average. In February 2020, the continent recorded its highest temperature of 18.3 °C (64.9 °F), which was a degree higher than the previous record of 17.5 °C (63.5 °F) in March 2015. There is some evidence that surface warming in Antarctica is due to human greenhouse gas emissions.

 The Antarctic peninsula has lost a number of ice shelves recently. These are large areas of floating ice which are fed by glaciers. Many are the size of a small country. The sudden collapse of the Larsen B ice shelf in 2002 , took 5 weeks or less and may have been due to global warming. Larsen B had previously been stable for up to 12,000 years. Concern has been expressed about the stability of the West Antarctic ice sheet. A collapse of the West Antarctic ice sheet could occur "within 300 years [as] a worst-case scenario. Rapid sea-level rise (>1 m per century) is more likely to come from the WAIS than from the [Greenland ice sheet]." 

The continent-wide average surface temperature trend of Antarctica is positive and significant at >0.05 °C/decade since 1957. The West Antarctic ice sheet has warmed by more than 0.1 °C/decade in the last 50 years, with most of the warming occurring in winter and spring. Research published in 2009 found that overall the continent had become warmer since the 1950s, a finding consistent with the influence of manmade climate change: A 2018 systematic review of all previous studies and data by the Ice Sheet Mass Balance Intercomparison Exercise (IMBIE) found that Antarctica lost 2720 ± 1390 gigatons of ice during the period from 1992 to 2017, enough to contribute 7.6 millimeters to sea level rise once all detached icebergs melt.

 IMPACTS ON THE NATURAL ENVIRONMENT

 Climate change / Global warming, resulting in a warming of the sea and loss of sea ice and landbased ice, this is greatest long-term threat to the region. Already some ice shelves have collapsed and ice slopes and glaciers have retreated. Oceanic acidification (from extra dissolved carbon dioxide) is already leading to the loss of some marine snails thought to have a significant part to play in the oceanic carbon cycle. The continued effects of climate change is likely to be felt by animal populations as well. The breeding populations and ranges of some penguin species have been altered. Adélie penguins, a species of penguin found only along the coast of Antarctica, may see nearly one-third of their current population threatened by 2060 with unmitigated climate change. 

Emperor penguin populations may be at a similar risk, with 80% of populations being at risk of extinction by 2100 with no mitigation. With Paris Agreement temperature goals in place, however, that number may decline to 19% under the 2 °C goal or 31% under the 1.5 °C goal. Warming ocean temperatures have also reduced the amount of krill and copepods in the ocean surrounding Antarctica, which has led to the inability of baleen whales to recover from pre-whaling levels. Without a reversal in temperature increases, baleen whales are likely to be forced to adapt their migratory patterns or face local extinction. 

What could HAPPEN if sea ice melts in ANTARCTICA by 2070??

 Sea levels will rise and all coastal countries could be seriously threatened by flooding if nothing is done to stop the massive melt of sea ice in Antarctica, according to nine award-winning scientists who have spent decades studying Antarctica the waters around it. And although we may never get to see Antarctica for ourselves
, these scientists want us to know that what happens in this remote region has a significant impact in our own backyard. 

if no one does anything to reduce greenhouse gas emissions and the planet continues to warm, the Southern Ocean and Antarctica could see a major melt: About a quarter of the volume of the sea ice would probably disappear by 2070. 2070, the sea would probably rise about half a meter from where it was in 2000. US coasts would probably see even higher sea rise, which would wreak havoc and be irreversible.

 It would cause an estimated $1 trillion in damage in the United States alone, researchers believe. The water in the Southern Ocean could become corrosive to any animal with a shell. 

The warmer ocean would create more icebergs, which would have to be carefully watched to protect fishing, shipping, and tourism. Fishing would get harder since fish stocks would decline. There would be severe declines in penguins and other die-offs of seabirds and seals. 

But we can have a much better scenario than this if: 

the world works together and makes pollution a priority, limiting greenhouse gases – only then there is a chance Antarctica could look much like it does now. The ice sheets would still be thinning, but that could slow, as would an increase in ocean acidity. Some of the more sensitive species would still see population declines, but others would adapt. The continuing decline of sea ice would still be forcing seal and seabird populations to change the way they forage for food, and these animals may still have some challenges with breeding, as we see today, but sea ice stabilization could reduce the frequency with which extreme events happen and hurt these species. Technology developed to redesign Antarctica's bases in the wake of these changes could be used to improve building and waste management in other parts of the world.